In the management of certain injuries to the lower extremities, such as fractures of the tibia and fibula, malleolar fractures, or severe ankle sprains, it is common to completely immobilize the lower extremity (following open or closed reduction in the case of fractures) by use of the well-known molded plaster or resin cast.
After the injured extremity has become stable, however, it has been found that recovery may be effected more rapidly by gradually and progressively permitting the extremity to bear weight and undergo other permitted exercises. Thus, for example, during a second stage of management, a walking heel may be attached to a long plaster cast, or the latter replaced by a shorter unit, or by a walking cast specifically adapted to facilitate such maneuvers.
One form of walking cast commercially available under the trademark AIRCAST is described in U.S. Pat. No. 3,955,565. Additional types of orthopedic devices which permit substantially normal plantoflexion and dorsoflexion movements of the ankle but limit inversion and eversion, thus stabilizing the ankle, are also commercially available such as those described in U.S. Pat. No. 4,280,489.
In order to maintain such orthopedic devices in proper fitting engagement about the lower extremity, a pair of longitudinally-spaced, circumferentially extending fastener straps with loops, generally available under the trademark VELCRO, are usually adapted to cooperate with first and second surfaces having circumferentially-spaced fastener hooks.
The fastening material sold under the trademark VELCRO generally comprises two components. Each component has a flexible backing material having a surface thereon. One surface is comprised of the resilient hooks, while the other is comprised of a short-pile, looped fabric. As the two fastening surfaces are pressed together, the hooks releasably engage the loops, thus releasably holding the fastening materials together. The fastening surfaces are separated by pulling them apart with sufficient force to cause the resilient hooks to straighten sufficiently to come out of engagement with the loops.
Previously, VELCRO-fastener hooks were secured by conventional methods to the exterior surface of orthopedic devices. The strap loops were then adapted to matingly engage the corresponding hooks so that the strap loops could be drawn and tensioned snugly against the exterior of the orthopedic device for placement next to the lower leg or ankle. Various other methods for attaching the hooks to the orthopedic device have been utilized in the past as well. All such prior conventional methods, however, provided for the hooks to be attached to the orthopedic device after the orthopedic device was molded and formed. The present invention, however, allows the hooks to be injection-molded as an integrally-formed part of the orthopedic device.
Typically, the prior fastening hooks were manufactured attached to the surface of orthopedic devices and other devices by the use of adhesives, ultrasonic welding, stitching or through the use of continuous extrusion molding. Such former methods of manufacturing and attaching the hooks and loop fastening materials have been described in U.S. Pat. Nos. 4,814,036, 4,470,857, and 4,726,975. Improvements to the traditional, adhesive, ultrasonic welding or stitching methods have occurred through advancements in the overall process of molding the fastener material strips by extrusion molding techniques, such as those disclosed in U.S. Pat. Nos. 4,814,036, 4,563,380, 4,872,243 and 4,794,028.
All of the prior methods of attaching the hooks to various devices, including orthopedic devices, have required the use of extensive labor in the process of either cutting and applying the hooks to the previously formed orthopedic device or through the use of extrusion molding.
As the use of VELCRO-type hooks and loop fasteners has increased, however, the industry has sought less labor intensive and costly methods of manufacturing and attaching these hooks.
The present invention eliminates many of the disadvantages inherent with such prior labor-intensive and material-expensive processes of extrusion molding, adhesive and stitching by integrally forming the hooks with the orthopedic device during the injection-molding process. The present invention thereby eliminates the separate step of attaching the hooks during production.